Optical surfaces such as those associated with eyeglass lenses and small electrical display devices are susceptible to dirt collection and smudging. This is particularly true if the surface is a polymeric material. Typically the surface is cleaned by spraying a cleaning solution such as a surfactant dissolved in a water-alcohol mixture and wiped with a cloth or paper towel. However, this cleaning treatment is temporary and offers no lasting protection for dirt collection or smudging.
To provide more lasting protection, it is known to apply hydrophobic coatings to optical surfaces. These coatings can be based on fluoropolymers and provide a somewhat more durable coating which typically lasts from 1 to 2 weeks depending on the hydrophobic material and on the surface being treated. Typically the hydrophobic material is applied by spraying and wiping the excess material from the surface being treated. Although this is an acceptable method for treating large surfaces such as those associated with television screens and computer-screens, it is not particularly effective for treating smaller optical surfaces such as those associated with eyeglass lenses or small electro-optical display devices such as cellular phones and personal data assistants. Spray applying the hydrophobic composition covers not only the optical surface but also to the surrounding surfaces where it is not needed. This results in a waste of a relatively expensive composition.
Also, it is known to apply hydrophobic compositions to windshields using an applicator that comprises a housing in the shape of a deodorant bar with an applicator that dispenses the hydrophobic composition by pressing the applicator tip against the windshield surface and wiping the tip across the surface. However, the hydrophobic composition is a polysiloxane, which does not adhere well to many substrates, particularly polymeric substrates. Even when applied to glass, the applied coating lacks permanency.
The present invention overcomes the above problems by providing a method and an applicator for applying a hydrophobic composition to a surface in which the composition is applied to the surface without wasteful overspray.